#include <string.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <stdio.h> #include <arpa/inet.h> #include <unistd.h> #include <stdlib.h> #define MYPORT 5555 // the port users will be connecting to #define BACKLOG 10 // how many pending connections queue will hold #define BUF_LEN 200 int main(void) { int sockfd, new_fd; // listen on sock_fd, new connection on new_fd struct sockaddr_in my_addr; // my address information struct sockaddr_in their_addr; // connector's address information int sin_size; int yes = 1; int retval; sockfd = socket(PF_INET, SOCK_STREAM, 0); // do some error checking! // tento radek zpusobi, ze pri opakovanem restartu serveru, bude volani // funkce bind() uspesne, kdo neveri, at ho zakomentuje :)) if(setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes)) == -1) { perror("setsockopt"); exit(1); } my_addr.sin_family = AF_INET; // host byte order my_addr.sin_port = htons(MYPORT); // short, network byte order my_addr.sin_addr.s_addr = INADDR_ANY; // auto-fill with my IP memset(&(my_addr.sin_zero), '\0', 8); // zero the rest of the struct retval = bind(sockfd, (struct sockaddr *)&my_addr, sizeof(struct sockaddr)); if (retval != 0) { perror("bind"); exit(1); } while (1) { char *msg = "Hello, this is server\n"; size_t len; char buffer[BUF_LEN]; retval = listen(sockfd, BACKLOG); if (retval != 0) { perror("listen"); exit(1); } printf("Server is waiting for connection\n"); sin_size = sizeof(struct sockaddr_in); new_fd = accept(sockfd, (struct sockaddr *)&their_addr, &sin_size); if (new_fd < 0) { perror("accept"); exit(1); } printf("Client connected from %s:%d\n", inet_ntoa(their_addr.sin_addr), ntohs(their_addr.sin_port)); send(new_fd, msg, strlen(msg), 0); while ((len = recv(new_fd, buffer, BUF_LEN-1, 0)) > 0) { buffer[len] = '\0'; /* mark end of string */ printf("Message from client: %s\n", buffer); } printf("Client %s:%d closed connection\n", inet_ntoa(their_addr.sin_addr), ntohs(their_addr.sin_port)); close(new_fd); } }